Creating spells

[Vigninou Gammadigbe]

Hello to all!

First of all, I would like to thank the users of this forum who helped me a lot in my learning of Stata software.

I'm asking you today to solve a problem with the creation spells. Indeed I have a panel database of countries observed on a monthly basis. The variable disaster is coded as follows: it takes the value 1 when a climatic phenomenon takes place in a specific month. If the disaster lasted more than one month then the variable takes the value of -1 the month it ended.

I would like to create a new variable (disacter2) from a stata code which will take the value of 1 on the period of phenomenon and zero otherwise. As an illustration I have created this variable (disester2) in Excel.

I would be grateful if you could help me to create this variable in stata. Thanks

* Example generated by -dataex-. For more info, type help dataex
clear
input int year byte month str3 country_code byte(disaster disaster2) float period
2018  1 "BEN"  0 0 696
2018  2 "BEN"  0 0 697
2018  3 "BEN"  0 0 698
2018  4 "BEN"  0 0 699
2018  5 "BEN"  0 0 700
2018  6 "BEN"  1 0 701
2018  7 "BEN"  0 0 702
2018  8 "BEN"  0 0 703
2018  9 "BEN"  0 0 704
2018 10 "BEN"  0 0 705
2018 11 "BEN"  0 0 706
2018 12 "BEN"  0 0 707
2019  1 "BEN"  0 0 708
2019  2 "BEN"  0 0 709
2019  3 "BEN"  0 0 710
2019  4 "BEN"  0 0 711
2019  5 "BEN"  1 1 712
2019  6 "BEN"  0 1 713
2019  7 "BEN"  0 1 714
2019  8 "BEN"  0 1 715
2019  9 "BEN"  0 1 716
2019 10 "BEN"  0 1 717
2019 11 "BEN" -1 1 718
2019 12 "BEN"  0 0 719
2020  1 "BEN"  0 0 720
2020  2 "BEN"  0 0 721
2020  3 "BEN"  0 0 722
2020  4 "BEN"  0 0 723
2020  5 "BEN"  0 0 724
2020  6 "BEN"  0 0 725
2020  7 "BEN"  0 0 726
2020  8 "BEN"  0 0 727
2020  9 "BEN"  0 0 728
2020 10 "BEN"  0 0 729
2020 11 "BEN"  1 1 730
2020 12 "BEN"  0 1 731
2021  1 "BEN"  0 1 732
2021  2 "BEN"  0 1 733
2021  3 "BEN"  0 1 734
2021  4 "BEN"  0 1 735
2021  5 "BEN" -1 1 736
2021  6 "BEN"  0 0 737
2021  7 "BEN"  0 0 738
2021  8 "BEN"  0 0 739
2021  9 "BEN"  0 0 740
2021 10 "BEN"  0 0 741
2021 11 "BEN"  0 0 742
2021 12 "BEN"  1 0 743
2018  1 "BFA"  0 0 696
2018  2 "BFA"  0 0 697
2018  3 "BFA"  0 0 698
2018  4 "BFA"  0 0 699
2018  5 "BFA"  0 0 700
2018  6 "BFA"  1 0 701
2018  7 "BFA"  0 0 702
2018  8 "BFA"  0 0 703
2018  9 "BFA"  0 0 704
2018 10 "BFA"  0 0 705
2018 11 "BFA"  0 0 706
2018 12 "BFA"  1 1 707
2019  1 "BFA"  0 1 708
2019  2 "BFA"  0 1 709
2019  3 "BFA"  0 1 710
2019  4 "BFA"  0 1 711
2019  5 "BFA"  0 1 712
2019  6 "BFA"  0 1 713
2019  7 "BFA" -1 1 714
2019  8 "BFA"  0 0 715
2019  9 "BFA"  0 0 716
2019 10 "BFA"  0 0 717
2019 11 "BFA"  0 0 718
2019 12 "BFA"  0 0 719
2020  1 "BFA"  0 0 720
2020  2 "BFA"  0 0 721
2020  3 "BFA"  1 0 722
2020  4 "BFA"  0 0 723
2020  5 "BFA"  0 0 724
2020  6 "BFA"  0 0 725
2020  7 "BFA"  0 0 726
2020  8 "BFA"  1 1 727
2020  9 "BFA"  0 1 728
2020 10 "BFA"  0 1 729
2020 11 "BFA"  0 1 730
2020 12 "BFA"  0 1 731
2021  1 "BFA"  0 1 732
2021  2 "BFA"  0 1 733
2021  3 "BFA" -1 1 734
2021  4 "BFA"  0 0 735
2021  5 "BFA"  0 0 736
2021  6 "BFA"  0 0 737
2021  7 "BFA"  0 0 738
2021  8 "BFA"  0 0 739
2021  9 "BFA"  0 0 740
2021 10 "BFA"  0 0 741
2021 11 "BFA"  0 0 742
2021 12 "BFA"  0 0 743
2018  1 "CIV"  1 0 696
2018  2 "CIV"  0 0 697
2018  3 "CIV"  0 0 698
2018  4 "CIV"  0 0 699
end
format %tm period

[Clyde Schechter]

isid country period, sort

frame put country_code disaster period if disaster != 0, into(endpoints)

frame endpoints: by country_code (period), sort: gen int next_endpoint = disaster[_n+1]

frlink 1:1 country_code period, frame(endpoints)
frget next_endpoint, from(endpoints)
drop endpoints
frame drop endpoints

by country_code (period): gen wanted = sum((disaster == 1 & next_endpoint == -1) ///
    - (disaster[_n-1] == -1))

[Vigninou Gammadigbe]

Hello Mr. Clyde Schechter,

I have tried your code and it works perfectly. I would like to thank you very much for your legendary availability and your great support. It is really greatly appreciated! God bless you!!!